I've been working on a project for which I would use a LED display to simulate a visual. The most cost-effective way to achieve this is by getting a LED indicator board such as used in this  topic.

The indicator board in question wasn't available any more, so I chose a different option, which also had an r232 connection. However, when I received it, and tried to connect with it through processing, it went flat. The cables were not the problem, nor my computer, since other connected hardware worked perfectly. I think it may be a fault in the indicator board, but I can't of course be certain.

Has anyone else got experiences with certain manufacturers and any success? (I live in Europe, and these indicator boards vary a lot locally) There aren't many stores around selling these things, and they all eye me strangely when I ask them If I can check if it works. And so far I had little luck.

Thanks!